Multipurpose control valve



Aug. 12, 1952 w. ERNST MULTIPURPOSE CONTROL VALVE 5 Sheets-Sheet l Filed Oct. 22, 1948 Aug. 12, 1952 W ERNST 2,606,571

MULTIPURPOSE CONTROL VALVE Filed Oct. 22, 1948 5 Sheets-Sheet 2 lIIIIIIIIIIIIII lll INVENTOR WALTER ERNST ATTORNEYS Aug. l2, 1952 Filed oct. 22, i948 w. ERNST 2,606,571

MULTIPURPOSE CONTROL VALVE 5 Sheets-Sheet I5 W. ERNST Y MULTIPURPOSE CONTROL VALVE Aug. 12, 1952 Filedl oct. 22. 1948 5 Sheets-Sheet 4 lNvENToR wALTE ERNST ATTORNEYS Aug. 12, A1952 W, ERNST 2,606,571

' MULTIPURPOSE CONTROL VALVE Filed Oct. 22, `194:8 5 Sheets-Sheet 5 INVENTOR WALTER vERNST ATTORNEYS Patented Aug. l2, 1952 UNITED STATES t\'i,`ff.'l\l'f ortica` MULTIPURPOSE CONTROL VALVE Walter Ernst, Dayton, Ohio, assigner, by mesne assignments, to The Thompson Grinder Company, Springfield, Ohio, acorporation of Ohio Application OctoberZZ, 194,8, SerialNo. 55,9134

Claims. (C1. 137-270,)

This invention pertains to improvements in Iiuid pressure control valves, and isparticularly related to an improved type of multi-purpose valve which may be readily used with but minor adjustments therein, to provide a Wide variety of pressure control in hydraulic circuits. v

The general term of pressure control comprises valves which have the function ci controlling the pressure existingV in the hydraulic circuit, and in particular, of controlling the magnitude of this pressure.

Heretofore, a number of individual devices have been used, distinguished from each other by the function that they perform in lthe hydraulic circuit, and all having the common purpose of controlling the maximum pressure existing either in the circuit or in a part of the circuit. Accordingly, there are relief valves which control the maxim-um pressure existing in an entire circuit` and prevent overload on pump and circuit. The relief valve will permit the flow of hydraulic viiuid to escape to the tank Whenever the maximum pressure is reached and will continue lto maintain this maximum pressure.

Another pressure contro-1 is the unloading valve, which is used to `control one of the pressures ina tv/vofpressure circuit. When` this pressure is reached the vdevice producing it is unloaded by meansof the unloading Valve which is operated by the second source of pressure.

Another device used is the reducing valve. The

purpose of this valve is to produce a xed lower pressure in a part of the circuit and maintain that pressure regardless of pressure fluctuation in the rest of the circuit.Y

Another device is the dual pressurerelief valve. This type of valve permits relief of pressure at a predetermined value, but by manipulation of an auxiliary directional control permits a much lower pressure to prevail in the system. Thus, during certain periods of operation in an hydrantlic circuit, it is possible to lower the circuit pressure very considerably, which is an advantage in idle periods for operation of machine tools,` etc., to cut down the amount of power consumption.

Another type of pressure control valve is the reverse now resistance valve. The purpose of the the resistance valve is to prevent a` vertical ram from dropping by gravity. To permit descent of this ram, it is necessaryvto supply a positive pressure before the resistance valve opens. When it is intended to return the ram free flow or substantially free flow, is provided. Generally, this is done bya built-in check valve.

nnotherpressure control device is the stl-called sequence valve. The purpose of this .valve is Ato eniorce a pre'determinedV sequencer in the operaf tion oihydra-ulic devices. It is so arranged that the rlrst device is directly connected'to a pump and operates as soon as pressure Vbegins to rise. When this pressure has Vreached a predetermined magnitude, thesequence valve Wil-l openand a'd.

mit pressure to the second device'and 'so on. Thus, a predetermined sequence, of operations in the hydraulic circuit is assured. 'A

Almost all of these devices have been developed individually .by -diftotoot mooufootutoro the oo@- velopment coincided with the necessity of application, and little or no consideration was given to their interrelatedcharacteristics.

The fact is, there arecertaip basic principles of operation inherent in all of these devices, and

by bringing them boekte a common deoomiootor, it is possible to perform all of the desiredfunctions with one ond the Somoboso Yolioby @holleing of passages by oonvooiontly provided Pipo plugs ,and throughv arrangement of the standardized parts. Thus,` with one setl of standardized parts4 it is possible to produce the entire line of pressure controls.

'Thereforev one of: the .objects or this. invention is to provide a ,simplified volvo Strutture W-hioh, may be readily altered to ooriorm a series ,of-V

different types of contr-o1 function sin a hydraulic circuit by slight modifications and adjustments ofthe valve.

It is aiurther object of this invention to provide a multi-purpose valve arranged in such ayvay that a series of ldiierent control yfunctims may bo obtained by minor roodiostmoots of o tow-,polito of the valve.

Hurt-.her features. andodyantagos of this. intonv Figure 5 is a` circuit diagram utilizing ,thevalve of Figures Y3 and 4 as o resistance. valve ,in ,o hydraulic circuit.

Figure 6 .is a sectonfthrough the volveodoptod as a `dual pressure relief valve, ndiootodby .the line 6;-6 in Figure .7.

Figure 7 is a section on the line 1-1 of Figure 6.

Figure 8 is a section through the valve adapted as sequence valve indicated by the line 8 8 Figure 9.

Figure 9 is a section on the line 9-9 of Figure 8.

Figure 10 is a section through the valve adapting it foruse as a reverse ow resistance valve, indicated by the line 0 of Figure l1.

Figure 11 is a section on the line of Figure 10.

Figure 12 is a section through the valve adapted to perform a reducing valve function indicated by the line |2|2 in Figure 13.

Figure 13 is a section on the line |3|3 of Figure 12.

Figure 14 is a hydraulic circuit diagram showing a specific application of the reducing valve of Figures 12 and 13 in combination with a throttle valve to produce constant flow regardless of resistance.

Referring to Figures 1 and 2 there is shown the basic form of the valve arranged as a simple relief valve comprising a body portion 20 having a central bore 2| in which is operatively slidable the Valve plunger 22 having enlarged spool portions 23 and 24 which slidingly engage the bore 2| and between which is provided the annular groove 25.

The lower face 26 of the plunger 22 is held against the bottom face 21 of the bore 2| by biasing springs 28 and 29 which bear against a flanged bushing 30 on top of the reduced end portion 3| of the plunger 22 and which engage in the top of the threaded cap 32 mounted on the valve bonnet 33 which in turn is suitably bolted to the valve body 20 by suitable screws 34. The threaded connection at 35 between the cap and the bonnet is closed by a suitable packing 36 to prevent leakage of fluid at this point.

An annular groove 31 formed in the valve body 20 around the bore 2| communicates with a passageway 38 while a second annular groove 39 in the valve body 26 communicates with a passageway 40 in the valve body. A passageway 4| in communication with the passageway 46 communicates with a passageway 42 and 43 in the valve bonnet 33 which in turn communicates withl the central bore 44 in the bonnet containing the'spring 28 and 29. A second passageway 45 also communicates with the central bore 44 and may be closed oif with a suitable pipe plug 46 in' this particular arrangement for use as a relief valve.

A chamber 41 at the bottom of the plunger 22 communicates with a passageway 48 which may be closed olf by a suitable pipe plug 49 when the valve is in use as a relief valve. A pilot plunger 50 has an enlarged head portion 5| and a reduced portion 52 which nicely slidably ts in a bore 53 formed in the valve body 20, and engages the bottom face 26 of the valve plunger 22. A uid pressure chamber 54 surrounds the pilot plunger and may be connected to a source of fluid pressure through a threaded opening 55 in a plate 55a held to the valve body 20 by suitable screws 55h. In Figure l, opening 55 is closed off by a pipe plug 56.

Referring particularly to Figure 2, communicating with the annular groove 31 is a passageway 51 which communicates with a passageway 58 having a valve seat 59 engageable by a check valve ball 60 actuated by a spring 6| which is carried in a passageway 62 in communication with a passageway 63 connected into the pressure chamber 54 for actuating the pilot plunger. A second passageway 64 is connected through a passageway 65 to passageway 66 also in communication with the pressure chamber 54 for the pilot plunger. A pin 61 of somewhat smaller diameter than the passageway 65 is placed therein and held in operative position by a suitable pipe plug 68 in the valve body 2E). A suitable pipe plug 69 provides access to the chamber 62, the spring 6| and the check valve ball 60.

In this arrangement of the valve as a relief valve, a source of fluid pressure from a pump P is connected to the passageway 38 while the passageway 46 is connected to the return line R. Under these conditions pressure builds up in the chamber 38 in the annular groove 31 and also passes out through the passageway 58 through the check valve 60 into the pressure chamber 54 to cause the pilot plunger 56 to rise and lift the valve plunger 22 in opposition to the springs 28 and 29 when the desired output pressure of the pump P has been reached. The connection to the pressure chamber 54 from the annular groove 31 through the passageway 65 choked by the pin 61 prevents chattering of the pilot plunger in maintaining proper positioning of the Valve plunger 22 in maintaining the desired operating pressure. It will be noted that no return flow through the check Valve 60 can occur so that when pressure is built up in the system suddenly it will pass through the check valve and under the pilot plunger and lift the balanced valve plunger 22. This causes a sudden drop of pressure which would cause the valve plunger to seat rapidly except for the choke escape opening in the passageway 65 in conjunction with the pin 61 which prevents too rapid a seating of the plunger.

In this arrangement the space formed by the bore 44 above the valve plunger is vented directly through the passageways 43, 42, and 4| to the drain passageway 4U which is connected to atmospheric return line.

A threaded passageway 10 in the bottom of the valve plunger 22 is left open at this time and communicates with a central bore 1| formed in the valve plunger 22 and being opened at its upper end and in communication with the bore 44 in the valve bonnet 33. Thus fluid trapped in the chamber 41 in the bottom of the valve plunger may readily escape up through the central bore 1| and finally discharge into the drain passageway 4E! of the valve. There is thus provided a valve arrangement which limits the pressure in the Huid pressure system when the pump P is operating and which will cause the pump to operate under this pressure continuously.

Another form of pressure control arrangement is shown in Figures 3 and 4 in which the basic valve arrangement of Figures 1 and 2 is revised to provide an unloading or forward pressure resistance valve function, that is to unload a pump in a hydraulic system at a given pressure by means of another pump operating at a higher pressure. In this arrangement a high pressure pump Pi is connected to the passageway 55 from which the pipe plug 56 has been removed, so that it communicates with the chamber 54 for the pilot plunger 50 while a lower pressure pump P2 is connected to the passageway 38. The pump P2 cannot act on the valve plunger nor on the area below the pilot plunger because both of the passageways 58 and 65 are plugged off by tightly fitting pins 12 and 13 placed in these passageways and held therein by the pipe plugs 68 and 69. Therefore, at the point where pressure in the system is built up to a predetermined valve, the

lhigh pressure pump Pl will lift the pilot plunger atte-,en

and allow the low pressure pump to bypass its fluid from the passageway 38 into the drain passageway 46. As the pressure builds up, the valve plunger will lift higher until the shoulder 'M on the pilot plunger has engaged the 'surface 'l5 of the valve body 20 so that the valve will be wide open and allow the low pressure pump to bypass freely. Thus low pressure pump P2 is permitted to bypass at substantially zero pressure, while the high pressure pump holds open the unloading valve. It is to be noted that this different functioning of the valve is accomplished with exactly the same parts as those used on lthe relief valve of Figures 1 and 2 by minor rearrangement of the openings and passageways. l

A Another function for which this multipurpose valvemay be used is that of acting as a resistance valve in a hydraulic circuit such as `shown in Figure 5 wherein a double acting cylinder 15 is supplied with fluid pressure from a pump Tl through a line 'i8' to a pressure chamber 19 behind its piston'l for the forward movement of the piston 8G and rod 8l., A line 18a connects pressure from the pump 'Vl to the threaded passageway 55 connected to the pressure chamber 54 of the valve 2li. The piston rod pressure chamber 82 of the cylinder l5 is connected through a line 83 to the passageway 'liil of the valve 2i! while the passageway 38 of this Valve is connected to the drain line 84. In this arrangement there will always be a positive pressure in the pressure chamber 82 of the cylinder regardless of the work load. For instance, as this arrangement is used to operate a drill press spindle and as the drilling is taking place if there is a sudden drop off of load, as in the case where the drill breaks through the work, theplunger 22 cannot lunge ahead because as soon as the pressure in the chamber 79 drops, the unloading valve connected to the chamber 32 will close, trapping the oil in the chamber 32. Here again we find standardelements combined to produce a new combination serving a somewhat diierent purpose than the original arrangement.

Still another application of this valve for a pressure control is 'shown in Figures 6 and '7 showing a dual pressure vrelief valve. This valve arrangement operates as a regular relief valve like that shown in Figures l and 2. ltshould be noted, however, that the diagonal passageway 48 is connected under lthe valve 'plungerZZ which inturn is connected 'through'a line 85 to a valve 86 which valve in turn is connected through a line 8l to the pressure supply line 88 from a pump 89 which is also vconnected to the passageway 38 of the valve`2ll.

` With the valve 86 so adjusted as to block off line 81 at the valve S5 and to connect the line 85 to the drain line 9@ and with the threaded passageway li) closed off by a Suitable plug 9| the valve functions the same as the valve arrangement of Figures 1 and 2. If at any point in the cycle of operation it is desired to drop the pressure in the system, the valve 86 is adjusted to connect pressure from line 81 to line 85 and to block off the drain line 90 so that the entire area of this valve is made available, that is, not only will pressure acting on the pilot plunger 50 operate to raise the valve plunger 22 but also pressure behind the valve plunger in the pressure chamber i7 will act on the valve plunger 2.2. Thus, the pressure will drop in the ratio that thear'ea of the relief Valve plungerbears to the area of the 'operating plunger. This ratio 'for instance, may be 5 to 1, which means thefoperating pressure in the system will drop down to 20% of the relief valve setting. With `this valve, it is possible to drop the operating pressure in the hydraulic system at any point in the cycle when this pressure is not needed and to thus conserve power. Y

Referring particularly to Figures 8 and 9 there is shown an arrangement of the multi-purpose valve adapting it to a sequence valve arrange'- ment. The purpose of this sequence valve arrangement is to permit pressure to buildup in one part of a hydraulic circuit, which is thje primary circuit indicated by the pump 92 for the pressure supply line 93 which is connected to the passageway 38 of the valve 23 and which has certain devices to be actuated connected to the line 93.

After this pressure has reached a fixed magnitude in the line S3, pressure passing into the pressure chamber 511 actuates the pilot plunger 5E lifting the valve plunger 2,2 and admitting pressure from the passageway 38 into the passageway di] which is connected to a secondary Circuit. As long as the pressure is above that required to open the valve as described, the valve will remain open supplying pressure from 'the primary circuit to the secondary circuit. If the pressure in the primary circuit drops below 'this setting of the valve, it will again close.

In principle, this valve arrangement is a relief valve relieving into ahydraulic circuit rather than into an atmospheric drain line, that is a drain line having no fluid back pressure. In order to accommodate the valve to this arrangement, a separate drain for the centralfbore "d4 in the bonnet 33 is `provided so that lthe back pressure in the secondary circuit cannot go back into the aforementioned central bore abovethe plunger and subject the plunger to opposing pressure. This is neatly accomplished in applicants arrangement by removing the screwsV 34 from the bonnet 33 and rotating the bonnet "18W to the position shown in 'Figure l0 so that the passageway's 42 and '43 are blocked oir at the blind hole 94 of the valve body 20 `and in whichv the pipe plug GB is removed to open the passageway 45 for connection to an independent atmospheric drain line 35. The screw holes for the screws 34 are arranged so `as to accommodate this turning of the valve bonnet 33 which is again clampedin position by the screws 34. This is the only modification necessary toproduoe sequence valve operation. Otherwise the principle of the valve is the sameas that shown in Figures l and 2 as described. The primary pressure acting against the pilot pressure passes through the check valve 60 and will open the sequence valve against a predetermined spring pressure as soon as the hydraulic pressure on the operating plunger has reached a value Sufficient to overcome the spring pressure, thus causing the primary pressure to escape into the secondary pressure outletllil. The valve will stay open as long as the pressure in the system hasa magnitude Arequired `to overcome the pressureof the springs 28 and 29. The choke valve 'El andthe check valve 68 are again provided to prevent chatter as described in connection with Figures 1 and 2.

In VFigures 10 and 1l there is shown a'formV of pressure control which is used to control, for example, the down speed of a hydraulic `press double acting ram descending by gravity. In this arrangement itis desired to'prevent descent bygravity and *rely n a vpositivepressure*to operate the ram at a predetermined speed. This valve is installed at the outlet of the retraction area 96 of the double acting cylinder 91 connected through a line 98 to the passageway 38 of the valve 20. Thus it is necessary to develop a pressure to push this ram down as by connecting pressure from a pump 99 through a line |00 and a selector valve and line |02 connected to the forward or downward pressure chamber |03 of the cylinder 91.

When it is desired to return the ram by the cylinder 91, the valve |0| is moved so as to connect the pressure line |00 through the valve |0| and the line |04 to the passageway 40 of the valve 20. A branch line |05 connected to the line |04 in turn is connected to the passageway 48 and the pressure chamber 41 is connected to the valve plunger 22 to act on the larger area of the valve plunger so that it will lift it a small fraction of the pressure required for the original valve setting. The valve plunger will be held with its shoulder 22a up against a fixed snap ring |06 positioned in a slot in the bore 2| of the valve body 20 so as to maintain intercommunication of the passageways 40 and 38 of the valve so that the pump pressure from the pump 99 is applied to the retraction chamber 96 of the cylinder 91 While the line |02 is connected through the selector valve |0| to the return drain line |01. In this arrangement the small opening 'l0 in the bottom of the valve plunger 22 is closed and a separate drain line provided for the bonnet 33 as in the case of Figure 8 is provided by appropriately positioning the bonnet 33 on the valve body 20. In this way pressure entering the passageway 40 cannot escape into the drain line so that it can be effective to return the ram.

As another arrangement to which this multipurpose valve is well adapted, there is shown in Figures 12 and 13 a reducing valve arrangement. In this case the valve plunger has been located differently than in all other cases so far described. The valve plunger 22 is positioned in an intermediate position of inter-communication between the passageways 38 and 40 of the valve by placing a slug |08 under the Valve plunger 22. Thus the Valve plunger is located so as to make a normally closed valve into a normally opened valve. The purpose of this reducing valve is to produce a xed pressure in a secondary outlet regardless of variations in the primary pressure supply. The valve operates by allowing free flow from the passageway 40 supplied with pressure from a pump |08 through a line ||0, into the passageway 38 of the valve. The action of the valve plunger 22 is controlled from the pressure in the passageway 38. As soon as the secondary pressure in the passageway 38 reaches a xed predetermined amount it will lift the valve plunger by means of the small pilot plunger 50 and cut ol communication between the passageways 40 and 38. Regardless of any variations in the pressure in the passageway 40, the secondary pressure in the passageway 38 will remain constant determined by the setting of the valve springs 28 and 29 and the screwed down position of the valve cap 32. If there is a tendency for pressure to leak out of the secondary system, the valve plunger will open connected from the primary pressure in the passageway 40 and apply fluid to the passageway 38 and thus make up the leakage. On the other hand if there is leakage of the primary pressure to the secondary pressure, the valve plunger will continue to rise until the secondary pressure relieves itself into the space below the valve plunger from Where it can escape through the central bore of the valve plunger to the drain line. For this use of the valve, the opening |0 is left unplugged.

A specic application of this reducing valve is illustrated in Figure 14 showing a reducing valve and a throttle combination to produce constant flow regardless of resistance imposed by the member being actuated. This is done by combining the reducing valve as shown in Figures 12 and 13 with an adjustable opening throttle valve T used to meter in a xed amount of fluid regardless of the pressure in the system or resistance to the movement of a hydraulic piston in a cylinder ||2 having a pressure chamber H3. As illustrated in Figure 14 a supply of uid pressure is provided by a pump ||4 through a line I5 to the passageway 40 of the valve and passes through the valve and then through a line ||6 through the throttle of the throttle valve T and then out through a line ||8 to the pressure chamber ||3 of the cylinder ||2. The flow of oil as it passes through the throttle valve T sets up resistance, and the resistance is transmitted back through the line ||6 to the pilot plunger 50, which regulates the valve plunger 22 to provide a xed pressure in the line ||6 behind the throttle valve T.

An auxiliary pipe line ||9 is connected between the passageway 45 in the bonnet of the valve into the line I I8 connected to the pressure chamber ||3 in the cylinder ||2 and the outlet of the throttle valve T. The central bore in the valve plunger 22 is opened and connects the top and bottom areas which are then subjected to the same pressure. This pressure also acts on the pilot plunger which is subjected to the pressure acting on the bottom, and on the pressure at the intake or in the line IIB of the throttle valve for the hydraulic pressure extending in that line which must balance the hydraulic pressure in the outlet from the throttle Valve plus the spring pressure of the springs 28 and 29 of the reducing valve. Therefore, the pressure in the intake of the throttle valve is always higher by a xed amount than the pressure in the outlet of the throttle valve. Therefore, there has been provided a xed pressure drop through the throttle valve which results in a constant flow regardless of the working pressure resisting in the system. By this particular arrangement, the minor addition of a simple throttle valve to the existing pressure control valve, a constant flow regulating valve may be produced that has patentable novelty.

And thus has been provided in a basic valve structure an arrangement whereby with a minimum of simple and easily adjusted and rearranged parts, a great number of pressure control functions may be provided for this multi-purpose valve by a novel ldesign of the valve structure, with, a minimum of eiort and time required to adapt the basic valve arrangement to accompany the essential hydraulic control features required in hydraulic circuits.

While the apparatus herein disclosed and described constitutes a preferred form of the invention it is to be understood that the apparatus is capable of mechanical alteration without de parting from the spirit of the invention and that such mechanical arrangements and commercial adaptations as fall within the scope of the appended claims are intended to be included herein.

I claim:

1. In a multi-,purpose valve having a valve body, :an'faxially reciprocatable valve plunger in said body, inlet and outlet ports associated with said valve .plunger adapted to be interconnected or cutoff from one another by the positioning of said plunger, a pressure chamber behind one end of said plunger including means to connect said chamber exteriorly of said valve body to a Vhydraulic circuit, a pilot plunger engaging said valve plunger, a second pressure'chamber in said valve `body associated with said pilot plunger including means for connecting said chamber exte- `riorly of said valve body to a hydraulic circuit,

a central bore .in said Valve plunger having means `:for connecting 'or closing .oli said central vbore fromsaid'iirst mentioned pressure chamber, and

,spring biasing means engaging the other end of .said valve :plunger to oppose a force exerted on said valve plunger by application ci uid pressure in either -or both ci said iirst and second Ypressure chambers.

2. In a multi-purpose valve having a valve body, an axially recip-rocatable valve plunger in said'body, inlet and outlet ports associated with said valve plunger adapted to be interconnected or cut off from one another by the positioning of said plunger, a pressure chamber behind one end of said plunger including means to connect said chamber exteriorly of said valve body to a hydraulic circuit, a pilot plunger engaging fsaid valve plunger, a second pressure chamber in lsaid valve body associated with said pilot plunger including means for connecting said chamber exteriorly of said valve body to a hydraulic circuit, a central bore in said valve `plunger having means `iorconnecthig or closing .olii said =central bore from said first mentioned pressure chamber, and 'spring biasing means engaging the other end` of said valve plunger to oppose a force exerted on -said Valve plunger by application of fluid pressure .in either or both of said rst and second pressure chambers, said spring biasing means being `carried in a central bore of a valve bonnet fixed .to said valve body, adjusting means for said spring means to regulate its pressure against the valve plunger comprising a threaded cap carried on said valve bonnet `and bolting means for holding said valve bonnet to said valve body in a` plurality of diierent positions so as to in one .position connect the central bore of the valve plunger and .the central bore in the bonnet tol one of the ports of said valve and in another position to provide an independent drain connection for said bores in the valve plunger and bonnet.

3. In a multi-purpose valve having a valve body, .an axially reciprocatable valve plunger in Vsaid body, inlet and outlet ports associa-ted with said valve plunger adapted to be interconnected Aor out ofi from one another by the positioning of said plunger, a pressure chamber behind one end of said plunger including means to connect said chamber exteriorly of said valve body to a hydraulic circuit, a 4pilot plunger engaging said valve plunger, .a second pressure chamber in said 4valve fbody associated with said pilot plunger in.-

cluding means for connecting chamber exteriorly of said valve body to a hydraulic circuit, a central `boire in said Valve plunger having means. for connecting or closing oil said central bore from `said iirst mentioned pressure chamber, and spring biasing means engaging the other end of .said valve plunger to oppose a force exerted on said valve plunger by application of iluidpressure in either or both of said rst and second pressure chambers, Said spring .biasing means 10 being carried in a central bore of a valve bonnet xed to said valve body, adjusting means for said spring means to regulate its pressure against the valve plunger comprising lav threaded cap carried on said valve bonnet and bolting means for holding said valve bonnet to said valve body in a plurality of different positions so as to in one position connect the central bore of the valve plunger and the central bore in the bonnet to one of the ports -of said valve and in another position to provide an independent drain connection for said .bores inthe valve plunger and bonnet, means associated with said valve lplunger for limiting its axial movement to a normally openedposition comprising a slug placed in said first mentioned pressure chamber.

4.111 a multi-purpose valve having a valve body, an axially reciprocatable valve plunger in said body, inlet and outlet ports associated with said valve plunger adapted to be interconnected Ior cut off from one another by the positioning of said plunger, a pressure chamber behind one end of said plunger including means to connect'said chamber exteriorly of said valve body to a hydraulic circuit, a pilot plunger engaging said valve plunger, a second pressure chamber in said lvalve body associated with said pilot plunger including means for connecting said chamber exteriorly of said valve body toa hydraulic circuit, a central bore in said valve `plunger having'means for connecting or closing ofi said central bore from said iirst mentioned pressure chamber, and spring biasing means engaging the other end `of said valve plunger to oppose a force exerted on said valve plunger by application of uid pressure in either or both of said iirst` and `second pressure chambers, said spring biasing means being carried in a central bore of a valve bonnet fixed to said valve body, adjusting means for said spring means to regulate its pressure against the valve plunger comprising a threaded cap carried on said valve bonnet and bolting means for holding said valve bonnet to said .valve body in aplurality of different positions so as to in one position connect the central bore of the Vvalve plunger and the central bore in the bonnet 'to one of the ports of said valve and in another position to provide an independent drain connection :for said bores in the valve plunger and bonnet, and means in said valve body to limit axial movement of said valve when pressure is `applied in either for both of said first and second mentioned pressure chambers to normally opened position in the direction opposed to said spring means.

L5. In a valve; a valve body having a owpassage with inlet and outlet ports, a valve plunger in said passage for controlling said ports, resilient means urging said valve plunger toward position to disconnect said ports, a Vplurality of pressure chambers at one end of said valve plunger to urge said valve plunger toward position to connect said ports, means for selectively supplying .pressure fluid to yone or more of said chambers, and

`channel means extending from said outlet port through said valve body and said valve plunger to one of said chambers said channel means being adapted for being selectively closed or opened to connect the said one chamber with the outlet port when the said chamber is not connected t'o a source of pressure, or to disconnect the said chamber from the port When `the chamber is to be used as a pressure chamber.

6. In a valve; a valve body having a how passage therethrough including inlet and 'outlet ports; .a .closed spring chamber on one end oi 11 the body, a valve plunger in said passage, spring means in said chamber urging said valve plunger toward position to disconnect said ports, a plurality of pressure chambers at the other end of said body for receiving pressure fluid to urge 'said valve plunger toward position to connect said ports, a channel extending from said outlet port to said spring chamber and through said plunger to the end thereof adjacent said pressure chambers, means for selectively supplying pressure iluid to said pressure chambers, and means in said plunger for selectively connecting or disconnecting said channel and one of said pressure chambers.

7. In a valve; a valve body having an axial bore extending inwardly from one end thereof, a pair of ports opening into said bore, a valve plunger in said bore adapted to bottom on the closed end of said bore and to form a pressure chamber therein; said member when so bottomed disconnecting said ports and being movable away Afrom its bottomed position through an intermediate position wherein said ports are connected and to a second end position wherein said ports are again disconnected, a spring urging said valve member toward its bottomed position, a pilot plunger extending into the closed end of said bore, means to supply pressure uid to the closed end of said bore and to said pilot plunger, and removable abutment means in said bore for halting said valve plunger in its intermediate position when acted on by pressure iiuid in the closed end of said bore or by said pilot plunger.

8. In a valve; a valve body having an axial bore extending inwardly from one end thereof,

a pair of ports opening into said bore, a valve plunger in said bore adapted to bottom on the closed end of said bore and to form a pressure chamber therein; said member when so bottomed disconnecting said ports and being movable away from its bottomed position through an intermediate position wherein said ports are connected and to a second end position wherein said ports are again disconnected, a spring urging vsaid valve member toward its bottomed position, a closed spring chamber on the said one end of the body housing said spring, a pilot plunger extending into the closed end of said bore, means to supply pressure fluid to the closed end of said bore and to said pilot plunger, and means comprising passages in the valve body and in the valve plunger adapted for being selectively interrupted for selectively connecting said spring chamber with or disconnecting it from one of said ports, the closed end of said bore, or exhaust for adapting said valve to a variety of fluid controlling purposes.

9. In a valve; a valve body having an axial bore extending inwardly from one end thereof, a pair of ports opening into said bore, a valve plunger in said bore adapted to bottom on the closed end of said bore and to form a pressure chamber therein; said member when so bottomed disconnecting said ports and being movable away vfrom its bottomed position through an intermediate position wherein said ports are connected V passages in the valve body and in the valve plunger adapted for being selectively interrupted for selectively connecting said spring chamber with or disconnecting it from one of said ports, the closed end of said bore, or exhaust for adapting said valve to a variety of uid controlling purposes, and a spacer member removably inserted between the bottom of said bore and said valve plunger for halting said plunger in its intermediate position when actuated by said spring.

10. In a valve having a valve body with a flow passage therethrough and a pair of ports opening into said passage; a valve plunger in said passage, movable into opposite end positions wherein said ports are disconnected and having an intermediate position wherein said ports are connected, spring means urging said plunger toward one of its end positions, uid operable means for urging said plunger toward the other of its end positions, and abutment means removably mounted in the valve body effective for engaging and halting said plunger in its intermediate position when it is acted on by one of said urging means.

11. In a valve having a valve body with a ow passage therethrough and a pair of ports opening into said passage; a valve plunger in said passage movable into opposite end positions wherein said ports are disconnected and having an intermediate position wherein said ports are connected, spring means urging said plunger toward one of its end positions, fluid operable means for urging said plunger toward the other of its end positions, and abutment means removably mounted in said valve body effective for engaging and halting said plunger in its intermediate position when it is acted on by said spring means, said last mentioned means comprising abutment means selectively positionable in said bore in the path of said valve member.

12. In a valve having a body with a bore with one closed end and a pair of ports; a valve plunger in said bore forming a pressure chamber with the closed end of the bore, said plunger having opposite end positions wherein said ports are disconnected and an intermediate position wherein said ports are connected, a closed spring chamber on said body at the open end of said bore and a spring therein urging said plunger towards the closed end of said bore and one of its end positions, channels extending from one of said ports to said pressure chamber and one including a check valve and another a choke, and means for selectively closing oil said channels.

13. In a valve having a body with a bore with one closed end and a pair of ports; a valve plunger in said bore forming a pressure chamber with the closed end of the bore, said plunger having opposite end positions wherein said ports are disconnected and an intermediate position wherein said ports are connected, a closed spring chamber on said body at the open end of said bore and a spring therein urging said plunger towards the closed end of said bore and one of its end positions, a pair of channels extending from one of said ports to said pressure chamber and one including a check Valve and the other a choke, another channel extending from said pressure chamber adapted for connection to point externally of said valve, means for selectively closing olf said channels, and abutment means selectively adjustable for halting said plunger in its intermediate position during movement from one of its end positions.

14. In a valve having a valve body with a flow passage therethrough and a pair of ports opening 15. An arrangement as set forth in claim 11` wherein the abutment means is a snap ring removably mounted in the bore, the said bore being 15 2,200,824

formed with a groove for releasably receiving said snap ring.

WALTER ERNST.

REFERENCES CITED The following references are of record ln the le of this patent:

UNITED STATES PATENTS 10 Number vName Date 228,493 Tyler June 8, 1880 347,213 Walker Aug. 10, 1886 1,294,151 Page '.Eeb.l 11. 1919 2,140,735 Clarke et al. Dec. 20, 1938 Herman May 14, 1940 

